The present invention generally relates to chemical-mechanical polishing (CMP) formulations, and more particularly, to CMP formulations for polishing or planarizing metal surfaces, such as tungsten.
Chemical-mechanical polishing or planarization (CMP) is a commonly used technique for the polishing and/or planarization of various substrates. CMP is particularly used in semiconductor fabrication for the polishing and planarization of metal-containing wafers. A metal commonly included in semiconductor wafers and for which CMP processing is required is tungsten (W).
CMP formulations generally include both an abrasive component (e.g., silica particles) and a corrosive component (e.g., periodic acid) in order to effectively polish a substrate surface using both mechanical and chemical processes. However, particularly for the case of metal substrates, and, in particular, tungsten, there has been an ongoing effort to find CMP formulations which can provide a higher etch rate while producing a uniformly polished surface according to the precise standards of the semiconductor industry. A higher etch rate corresponds to shorter process times, and thus, higher throughputs. Therefore, a significantly increased etch rate can result in significant cost savings for the process. There would be a further benefit if such improved CMP formulations are readily integratable into existing CMP processes and are of the same approximate cost as formulations commonly used in the art.